Anode deterioration indicator for water heaters



Dec. 6, 1955 w. A. MARSHALL EI'AL 2,725,205

ANODE DETERIORATION INDICATOR FOR WATER HEATERS Filed Sept. 2, 1952 2 Sheets-Sheet 1 51 1 s 33 P5 E 39 I i 2 7 jg 30/ lV/u/mw A. MARSHALL ANTHONY N Jr/J roN INVENTORS AT T ORNEY Dec. 6, 1955 w. A. MARSHALL ETAL 2,726,205

ANODE DETERIORATION INDICATOR FOR WATER HEATERS Filed Sept. 2, 1952 2 Sheets-Sheet 2 IN V EN TORJ' A TTORNEY United States Patent Ofifice 2,726,205 Patented Dec. 6, 1955,

ANODE DETERIORATION INDICATOR FOR WATER HEATERS William A. Marshall, Anthony N. Staten, and Erwin S. Kleinmann, Dallas, Tex., assignors to Dearborn Stove Company, Dallas, Tex.

Application September 2, 1952, Serial No. 307,542

Claims. (Cl. 204-197) This invention relates to indicators and more particularly to.- an indicator for use with anodes for indicating excessive deterioration or consumption of the anodes.

The sacrificialv anodes used in hot water heaters to reduce by electrolytic action the deterioration of water heater tanks due to corrosive action caused by the presence of two different metals in the, tank or connected thereto, arev subject. to deterioration. The magnesium anode is progressively consumed with use and does not, therefore, protect indefinitely the tank in which it is installed. After the, anode has been consumed or has deteriorated. to a certain extent, it fails thenceforth to perform its protective function and the tank itself will start det'erioiatingat a rate dependent on water conditions, and the. condition of. the tank itself. It is a common misap- Qrehension on the part of the general public, however,

that the original protective anode will serve its function indefinitely- It is desirable, therefore, to provide an indicator for such anodes which will indicate to the water heater user when the anode has been consumed or has deteriorated' to such an extent that replacement of the anode is necessary for the continued protection of the heater tank. The indicator should be of simple construction and operation, should be easily connected to the water heater tank, and should give a distinctive, very noticeable indication when the anode becomes excessively consumed or deteriorated.

Accordingly, it is an object of the invention to provide a new and improved indicator for giving a signal when excessive deterioration or consumption of an anode occurs.

It is another object of the invention to provide a new and improved anode having an indicator for giving a visual signal upon the occurrence of excessive consumption or deterioration of the anode.

It is another object of the invention to provide a new and improved indicator connected to an anode immersed in a fluid for causing a signal to be given by co-action of the fluid with the indicator upon the occurrence of excessivev consumption or deterioration of the anode.

It is a further object of the invention to provide a new and improved. anode having central longitudinal recess to which the fluidin which the anode is immersed enters when the anode deteriorates excessively and having means upon which the fluidv acts upon entering the recess to give a visual signal of this excessive deterioration.

Briefly stated, in one embodiment of the invention, the anode is provided with an internal tube having a perforate lower' portion embedded in the anode and having an upper portion extending beyond the upper end of the anode. A pressure gauge is connected to the upper end of the tube so that the pressurized fluid in which the anode is immersed will cause the gauge to give a visible signal when the anode deteriorates or is consumed to such a degree as to expose the lower perforate portion of the tube and allow the flow of fluid into the tube and thence to the gauge.

lnanother embodiment of the invention, the upper end 2 v of the tube is connected with an exposed sight glass and a wick extends through the tube into the sight glass. The wick passes through dye impregnated washers so that when the anode deteriorates excessively, fluid is transmitted by the wick to the washers to release the dye and thus give the desired signal.

In yet another embodiment of the invention, a fioat is disposed in the sight glass which rises to give the desired signal when fluid is permitted to enter the tube by the excessive deterioration of the anode.

In another embodiment of the invention, the perforate tube and the sight glass are filled with a soluble substance which dissolves to reveal a visual signal when fluid enters into the tube due to the deterioration of the anode.

In another embodiment of the invention, a perforate tube is embedded in the anode and filled with a dye which is released into the liquid in which the anode is immersed when the anode deteriorates to an excessive extent whereby the coloration of the liquid gives the desired signal.

In a final embodiment of the invention, the anode is dependent from a plunger which is upwardly biased by aspring and whose upper end projects into a sight glass. The plunger rises as the weight of the anode decreases. with deterioration to give the desired signal.

For a better understanding of the invention reference may be had to the following description taken in connec= tion with the accompanying drawing. and its scope will be pointed out in the appended claims.

In the drawing:

Figure 1 is a vertical sectional view of a water heater tank provided with an indicator employing a gauge;

Figure 2 is a vertical, partly sectional view of the anode and the indicator shown in Figure 1;

Figure 3 is a horizontal sectional view taken on the' line 3-3 of Figure 2;

Figure 4 is a vertical partly sectional view of another embodiment of the invention which includes a spring;

biased plunger;

Figure 5 is a vertical partly sectional view of the embodiment of the invention which includes the liquid transferring wick;

Figure 6 is a horizontal sectional view taken on theline 66 of Figure 5;

Figure 7 is a vertical partly sectional view of the em-- bodiment of the invention which includes the. dye filledv Referring now particularly to Figures 1, 2 and 3, the water heater tank 20 is disposed within a'protective and: heat insulating shell 21. The tank 20'has a bottom 22';

a cylindrical wall 23 and a top 24 which maybe integralwith the wall. The cold water inlet pipe 25 is threaded in a suitable inwardly turned flange or spud 26 ofpthe" top and has an extension 27 with onoutlet situatedinthe lower portion of the tank so that cold water enters at the lower end of the tank as hot water is. withdrawn.

from the upper end of the tank through anoutlet pipe 28 threaded in a flangeor spud 29 of the top. I

The anode 30, of magnesium or other suitable substance, is cast about a brass tube 31' whose upper end is telescoped in the brass fitting 32 and held rigidly therein by a press fit, by brazing, or in any' other suit= able manner. The fitting is externally threaded to engage the internally threaded spud 33 of the top 24 of the tank. The fitting has a central bore 34 communicating with the interior of the tube 31 which is internally threaded to receive the inlet-connection 35 of a pressure gauge 36. The tube 31 is provided with an elongate slot 37 in its lower portion which is normally closed by the anode 30 thus preventing the fluid in the tank which is, of course, under pressure, from entering into the interior of the tube and thus subjecting the gauge to the pressure. The hand 38 of the gauge will then be moved to indicate that the anode has been consumed or has deteriorated to such an extent that replacement thereof is necessary. The anode may easily be replaced by unscrewing the gauge from the fitting 32, and then raising the top 39 of the protective shell 21 to expose the top flange or nut 40 of the fitting. The top 39, or course, is provided with suitable apertures through which the inlet and outlet pipes of the tank and the inlet of the gauge may extend. The fitting is then unscrewed and the anode is lifted out through the bore of the spud 33. A new anode assembly may then be inserted into the tank and secured therein by means of its fitting, and the shell top 39 and gauge 36 replaced, the tank then being ready for further operation.

It will be understood that the tank is of metal, may be zinc lined, and may be connected to copper or brass fittings and pipes so that electrolytic action when the tank is filled with water will cause corrosion of the tank. The anode prevents this corrosion of the tank by a sacrificial electrolytic process which consumes or deteriorates the anode. Once the anode is consumed or deteriorated to an excessive degree or extent, it can no longer prevent the corrosion of the tank. For this reason, the anode must be replaced after it has deteriorated or has been consumed to a predetermined degree.

In Figure 4 is illustrated another embodiment or" the invention in which the anode is connected to the lower end portion 51 of a plunger 52 which engages in a suitable bore in the upper end of the anode and is held therein by a pin 53.

The plunger extends through the central bore of a fitting 54 having a threaded lower end 55 which can be screwed into the spud 33 in the top of a water tank. The fitting has an intermediate internal shoulder 56 which engages a flange 57 on the plunger to limit the downward movement of the plunger and a lower internal shoulder 58 against which bears the lower end of a compression spring 59 disposed about the lower portion 51 of the plunger. The upper end of the spring bears against the flange 57 so that the spring biases the plunger toward an upper position. The weight of the anode maintains the plunger in the position shown in Figure 4. As the anode is consumed, its weight decreases and the spring 59 moves the plunger upwardly. The top portion 53' of the plunger may be brightly colored so that it may be easily seen through the sight glass or cover 60 and the apertures 61 of a guard cup 62 when it is moved to an upper position upon the deterioration of the anode.

The sight glass 60 is cup shaped and has an outer annular flange 63 which rests on a gasket 64 disposed on the upper intermediate shoulder 65 of the fitting. The sight glass is held in place by the lower end of the guard cup which is threaded in the upper end of the fitting. A washer 66 is interposed between the annular flange 63 of the sight glass and the lower end of the guard cup. The sight glass may be provided with a mark 67 to cooperate with the upper portion 53 of the plunger to indicate when the anode has been consumed to such an extent that replacement is necessary. It will be evident that the remains of the old anode may be separated from the lower portion 51 of the plunger by removing the pin 53. A new anode may then be fastened to the plunger.

In Figures 5 and 6 is illustrated another embodiment of the invention in which an anode 70 is cast around a hollow brass tube 71 whose lower end is closed, as at 72, to prevent passage of fluid into the tube and whose upper end is telescoped in a fitting 73 and rigidly secured therein by a press fit, brazing or the like. A longitudinal slot 74 in the tube is normally closed by the anode. A cord or wick 75 extends through the-tube into a sight glass 76 secured on the upper end of the fitting. The upper end of the cord extends through a plurality of liquid permeable washers 77 of felt or other suitable material which abut the interior surface of the sight glass. A plurality of dye impregnated washers 78 of smaller diameter than the washers 77 are disposed between the washers 77.

The fitting 73 has an internal annular shoulder 79 on which the lowermost washer 77 rests. A gasket 80 also rests on the shoulder 79 below the lower annular flange 81 of the sight glass 76. The sight glass is retained in place by a guard cup 82 whose lower end is threaded in the upper portion of the fitting and abuts a washer 83 interposed between the lower edge of the guard cup and the upper surface of the annular flange 81 of the sight glass. The guard cup has apertures or windows 83 through which the sight glass may be observed. The fitting 73 has an externally threaded lower portion by which the assembly may be secured to the spud 33 of the top of the water tank.

In use, the anode 70 prevents any water from entering into the tube 71 until the anode is consumed to such an extent that the slot 74 is uncovered. The water then enters into the tube and wets the cord which conducts the water to the dye impregnated washers 78. The dye is water soluble so that as the washers 78 are wetted, the dye is released into the water. The dyed water then impregnates the washers 77 and this changes their color. This change in color may be observed through the windows 83' of the guard cup and through the sight glass. This change in color, of course, is a visible signal warning that the anode 70 must be replaced.

In Figures 7 and 8 is illustrated still another embodiment of the invention in which the anode is cast about the lower end portion of a hollow brass tube 91 whose upper end extends through the fitting 92 and is rigidly secured thereto by a press fit, breezing or in any other suitable manner. The tube 91 is then filled with a soluble dye and its upper end sealed. The fitting 92 has a threaded portion by means of which it may be secured in the spud 33 of the water heater tank.

In use, the anode 90 keeps the slot 93 of the tube closed until the anode is consumed to such an extent that the slot 93 is uncovered. The dye is then released into the water of the tank and colors the water. The change in the color of the water drawn from the tank through the outlet 28 gives the desired visible signal which indicates that the anode should be replaced.

The embodiment of the invention illustrated in Figures 9 and 10 comprises an anode east about a hollow brass tube 101 whose lower end is closed, as at 102 and whose upper end telescopes into a fitting 103 and is secured thereto by a press fit, brazing or in any other suitable manner. A float 104 is movably disposed in the bore of the fitting and normally rests on a lower annular shoulder 105 of the fitting. The float is adapted to move upwardly in a sight glass 106 secured to the upper end by a guard cup 107 which is threaded into the fitting. A gasket 108 is interposed between the upper annular shoulder 109 of the fitting and the annular flange 110 of the sight glass while a washer 111- is interposed between the lower edge of the guard cup and the upper surface of the annular flange of the sight glass. Windows or apertures 112 in the guard cup enable the float to be seen through the sight glass when it moves to an upper position.

In use, the anode keeps closed a longitudinal slot 113 of the tube 101 until the anode is consumed to such an extent that the slot 113 is uncovered. The water in which the anode is immersed then enters into the tube. The float 104 being buoyant is lifted up by the water and floats to an upper position where it is visible through the windows 112 of the guard cup. This gives a visual signal that the anode must be replaced. It will be noted that the lower portion of the float will be disposed below the top of the water tank when the fitting is threaded in the spud 33 of the water tank so that water will rise in the tube and in the fitting to the extent necessary to raise the float to the level of the windows. The water will tend to rise higher than the top of the tank in any case since it is normally under pressure.

In the embodiment of the invention illustrated in Figures 11 and 12, the anode 120 is cast about a brass tube 121 whose lower end is closed as at 122, and whose upper end extends through a fitting 123 into a sight cup 124. The fitting is secured to the tube by a press fit, brazing or in any other suitable manner. The fitting is secured to the spud 33 by external threads on the lower portion of the fitting while the sight glass is secured to the fitting by a guard cup 125:: threaded into the fitting. The sight cup has an annular flange 125 resting on a gasket 126 on the annular shoulder 127 of the fitting. A washer 128 is interposed between the lower edge of the guard cup on the upper surface of the annular flange.

The upper end portion 129 of the tube extends into the sight glass and is preferably painted a bright color. The upper end portion is provided with a plurality of apertures 130 for a purpose to be described. The tube 121 is provided with a slot 131 normally closed by the anode. Both the tube and the sight glass are filled with a water soluble substance 132 such as calcium chloride.

In use, the anode keeps the slot 131 closed until it is consumed to such an extent that the slot is opened. Water from the tank then enters into the tube dissolving the substance 132. The dissolution of the substance continues until the substance in the sight glass is also dissolved uncovering the painted upper end 129 of the tube which then becomes visible through the apertures or windows 133 in the guard cup. The apertures 130 in the upper end portion 129 facilitate the passage of the water into the glass sight.

It will be apparent that the tube and fitting may be made of any suitable electrically conductive substance so that electrical connection may be had between the tank and the anode. The tube may be secured to the anodes in any other suitable manner instead of by casting the anode about the tube if so desired. Circular or other shaped apertures may be provided in the lower portions of the tubes instead of the elongate slots.

Among the advantages of the embodiments of the invention described and illustrated is their case of installation and replacement, and their simplicity of design and operation which insures their proper operation to give the desired signal when the anode has been consumed or has deteriorated to such an extent that replacement thereof becomes necessary.

Manifestly, the construction (and process) as shown and described is capable of some modification and such modification as may be construed to fall within the scope and meaning of the appended claims is also considered to be within the spirit and intent of the invention.

What is claimed is:

1. In combination with an anode immersed in liquid in a tank for preventing corrosion of said tank, an automatically actuated device for indicating the degree of consumption of said anode comprising a fitting connected to said tank, a plunger movably mounted in said fitting, said anode being solely supported by said plunger and disposed in said tank and means imposing an outward biasing force on said plunger less than the submerged weight of said anode whereby said plunger moves outwardly as the weight of said anode decreases.

2. In combination with an anode immersed in liquid in a tank for preventing corrosion of said tank, said tank having a central aperture, a device for indicating the degree of consumption of said anode comprising a fitting extending into said central aperture, a plunger extending into said aperture, said plunger having its inner end connected to and supporting said anode, cover means connected to said fitting extending exteriorly of said tank and closing said central aperture, said plunger being movable outwardly in said fitting and cover means, and means exerting an outward biasing force on said plunger less than the submerged weight of said anode whereby said plunger moves outwardly as said anode is consumed, said cover means permitting observation of outward movement of said plunger.

3. In combination with an anode immersible in liquid in a tank for preventing corrosion of said tank, an automatically actuated device for indicating the degree of consumption of said anode comprising a fitting entering said tank and having a central aperture, a plunger reciprocable in said aperture having a portion entering said tank and supporting said anode therein, a cover sealing said aperture having transparent portions through which movement of said plunger is observable and means causing said plunger to move into visual range through the transparent portions of said cover as the weight of said anode is lessened by corrosion.

4. In an anode deterioration indicator for a water tank, a tank and an anode, a hollow fitting attached to said tank, a plunger disposed for longitudinal displacement in said hollow fitting and supporting said anode submerged in liquid in said tank, a cover for said fitting having apertures therein, and means normally exerting a force on said plunger less than the normal submerged weight of said anode for moving said plunger into a position for visibility through the apertures of said cover as the weight of said anode is reduced by corrosion.

5. In a device of the character described, a tank and an anode, a hollow fitting attached to said tank, a plunger disposed for longitudinal displacement in said hollow fitting and supporting said anode submerged in liquid in said tank, said plunger being held in receded position in said fitting by the weight of said anode and means effective to cause said plunger to move from its receded position in said fitting as the weight of said anode is lessened by corrosion.

References Cited in the file of this patent UNITED STATES PATENTS Lonergan Apr. 20, 1880 Cumberland Mar. 19, 1912 OTHER REFERENCES 

1. IN COMBINATION WITH AN ANODE IMMERSED IN LIQUID IN A TANK FOR PREVENTING CORROSION OF SAID TANK, AN AUTOMATICALLY ACTUATED DEVICE FOR INDICATING THE DEGREE OF CONSUMPTION OF SAID ANODE COMPRISING A FITTING CONNECTED TO SAID TANK, A PLUNGER MOVABLY MOUNTED IN SAID FITTING, SAID ANODE BEING SOLELY SUPPORTED BY SAID PLUNGER AND DISPOSED IN SAID TANK AND MEANS IMPOSING AN OUTWARD BIASING FORCE ON SAID PLUNGER LESS THAN THE SUBMERGED WEIGHT OF SAID ANODE WHEREBY SAID PLUNGER MOVES OUTWARDLY AS THE WEIGHT OF SAID ANODE DECREASES. 